Bidirectional signal transmission network and bidirectional signal transfer shift register

ABSTRACT

A bidirectional signal transfer shift register with a simple circuit construction is disclosed together with suitable applications of the same. The bidirectional signal transfer shift register comprises a plurality of flipflops each having an input terminal and an output terminal in pair. The input and output terminals of the flipflops are connected successively in such a manner as to construct a multi-stage structure. A forward route gate element is interposed in a connection route between the output terminal of the front stage side one of each two adjacent front and rear ones of the flipflops and the input terminal of the rear stage side flipflop, and a reverse route gate element is interposed in another connection route between the output terminal of the rear stage side flipflop and the input terminal of the front stage side flipflop. Forward direction signal transmission processing and reverse direction signal transmission processing can be switchably selected by alternatively controlling the forward and reverse route gate elements to open or close.

This is a continuation of application Ser. No. 08/264,483, filed Jun.23, 1994, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a bidirectional signal transmissionnetwork and more particularly to a bidirectional signal transfer shiftregister which is suitably incorporated, for example, in a drive circuitof an active matrix liquid crystal display device and used for reversaldisplay of an image.

2. Description of the Related Art

An active matrix liquid crystal display device is conventionally knownand has such a a general construction as shown in FIG. 6. Referring toFIG. 6, the active matrix liquid crystal display device (LCD) 100 shownincludes a liquid crystal layer 101 which exhibits a predeterminedelectro-optical effect and is held between a pair of transparent glasssubstrates 102 and 103. A plurality of picture element electrodes 104are formed on an inner surface of the substrate 102 and disposed in amatrix. A thin film transistor 105 made of polycrystalline silicon or alike material is connected to each of the individual picture elementelectrodes 104. The drain electrodes of the thin film transistors 105are connected to the corresponding picture element electrodes 104; thesource electrodes are connected to corresponding data lines 106; and thegate electrodes are connected to corresponding gate lines 107. Aplurality of opposing electrodes 108 are formed on an entire innersurface of the other substrate 103. An image data signal is written byway of the individual thin film transistors 105 into the correspondingpicture element electrodes 104. Electro-optical variations of the liquidcrystal layer 101 caused by the image data signal are detected astransmission light amount variations by means of, for example, a pair ofpolarization plates (not shown) to effect display of a desired image.

An active matrix liquid crystal display device having the constructiondescribed above can be utilized, for example, as a light valve for aliquid crystal projector. A liquid crystal projector includes threeliquid crystal display devices to which the three primary colors areallocated, and a common enlarging projection lens system. The liquidcrystal display devices function as light valves for the different colorsystems of red, green and blue. The liquid crystal display devicesresolve a primary image into red, green and blue components and displaythem. Red, green and blue illumination light beams are introducedsimultaneously into the liquid crystal display devices. Single colortransmission light images of the individual liquid crystal displaydevices are composed by means of a dichroic prism or a dichroic mirror,and a thus composed full color image is projected in an enlarged scaleonto a screen by the projection lens system. In the optical system ofthe liquid crystal projector, a primary image is composed afterreflection reversal is repeated several times. Depending upon thearrangement structure of the optical system, the number of times ofreflection reversal is different among the different color systems.Accordingly, in order to obtain an aligned full color image, a primaryimage component of a predetermined color must be displayed reversely inadvance. Or, depending upon installation environments of the liquidcrystal projector, it may possibly be mounted in an inverted posture ona ceiling to effect projection. Also in this instance, a primary imageto be displayed on the liquid crystal display device must be reversed inadvance.

In this manner, a structure which can suitably select reversal displaydepending upon an object of use or an application of the liquid crystaldisplay device is conventionally demanded. To this end, various imagereversing systems have been proposed conventionally. For example, such asystem as shown in FIG. 7 which makes use of image signal processing isknown. Referring to FIG. 7, an original image data signal SIG isinputted once to an analog to digital (A/D) conversion and reversalprocessing circuit 110, in which it is converted into a digital signaland then processed by reversal processing. For example, the data signalis successively written into a frame memory and then read out in thereverse direction. The data signal processed by the reversal processingis supplied to a liquid crystal display device 100 by way of a buffer111.

FIG. 8 shows another system for image reversal. Referring to FIG. 8, adownward scanning circuit 120 is connected to gate lines 107 of a liquidcrystal display device 100. An ordinary unidirectional shift registernot shown is incorporated in the downward scanning circuit 120 and sendsout a gate signal to the gate lines 107 successively beginning with theupper end and ending with the lower end of the screen. Also an upwardscanning circuit 121 is connected to other gate lines 107. Aunidirectional shift register not shown is incorporated also in theupward scanning circuit 121 and sends out a gate signal to the gatelines 107 successively beginning with the lower end to the upper end ofthe screen. The downward scanning circuit 120 and the upward scanningcircuit 121 in pair can be selected suitably. When the downward scanningcircuit 120 is selected, a normal or non-reversed image is displayed,but when the upward scanning circuit 121 is selected, a verticallyreversed image is displayed. Similarly, a rightward scanning circuit 122and a leftward scanning circuit 123 in pair are connected to data lines106. When the rightward scanning circuit 122 is selected, normal imagedisplay is performed, but when the leftward scanning circuit 123 isselected, a leftwardly and rightwardly reversed image is displayed. Itis to be noted that, while the four scanning circuits are shown disposedoutside the liquid crystal display device 100 in FIG. 8, it is possibleto actually form them in an integrated condition in the inside of theliquid crystal display device 100.

In the reversing system shown in FIG. 7 which makes use of image signalprocessing, since the A/D reversal processing circuit and so forth havea large scale, there is a problem to be solved in that the powerdissipation is high and reduction in size is obstructed, resulting indisadvantage in terms of the cost. Meanwhile, with the reversing circuitstructure shown in FIG. 8, there is another subject to be solved inthat, since four scanning circuits are required, where they are formedin the inside of a liquid crystal display device, the device requires alarge area and the yield is deteriorated as much.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a reversing systemfor an active matrix liquid crystal display device which is simple instructure and inexpensive.

It is another object of the present invention to provide a bidirectionalshift register which is suitable to drive an active matrix liquidcrystal device to display a reversed image.

It is a further object of the present invention to provide atwo-dimensional address device which can reverse the scanning direction.

It is an additional object of the present invention to provide abidirectional signal transmission network which can transmit a signal inthe opposite directions with a simple construction.

In order to achieve the objects described above, according to an aspectof the present invention, there is provided a bidirectional signaltransfer shift register, which comprises a plurality of flipflops eachhaving an input terminal and an output terminal in pair, the input andoutput terminals of the flipflops being connected successively in such amanner as to construct a multi-stage structure, a forward route gateelement interposed in a connection route between the output terminal ofthe front stage side one of each two adjacent front and rear ones of theflipflops and the input terminal of the rear stage side flipflop, and areverse route gate element interposed in another connection routebetween the output terminal of the rear stage side one of each twoadjacent front and rear ones of the flipflops and the input terminal ofthe front stage side flipflop.

The bidirectional signal transfer shift register having the constructioncan be applied, for example, to an active matrix liquid crystal displaydevice. In particular, according to another aspect of the presentinvention, there is provided an active matrix liquid crystal displaydevice, which comprises a first substrate on which a plurality of gatelines disposed along the direction of a row of a matrix, a plurality ofdata lines disposed along the direction of a column of the matrix, aplurality of active elements positioned at crossing points between thegate lines and the data lines, a plurality of picture element electrodesindividually driven by the active elements, a vertical drive circuit forsupplying a gate signal line-sequentially to the gate lines, and ahorizontal drive circuit for supplying a data signal line-sequentiallyto the data lines are formed, a second substrate disposed in an opposingrelationship to the first substrate and having a plurality of opposingelectrodes formed thereon, a liquid crystal layer held in a gap betweenthe first and second substrates, and a bidirectional shift registercapable of switchably controlling the line sequential supplying order ofthe gate signal or the data signal between two forward and reversedirections. The bidirectional shift register may be included in thevertical drive circuit so as to selectively allow vertically reverseddisplay of an image or alternatively included in the horizontal drivecircuit so as to selectively allow leftwardly and rightwardly reverseddisplay of an image.

The present invention can be applied not only to a bidirectional signaltransfer shift register but also widely to bidirectional signaltransmission networks. In particular, according to a further aspect ofthe present invention, there is provided a bidirectional signaltransmission network, which comprises a plurality of signal transmissionblocks each having an input terminal of a comparatively high impedanceand an output terminal of a comparatively low impedance, the input andoutput terminals of the signal transmission blocks being connectedsuccessively, a forward route gate element interposed in a connectionroute between the output terminal of the front stage side one of eachtwo adjacent front and rear ones of the signal transmission blocks andthe input terminal of the rear stage side signal transmission block, areverse route gate element interposed in another connection routebetween the output terminal of the rear stage side one of each twoadjacent front and rear ones of the signal transmission blocks and theinput terminal of the front stage side signal transmission block, andcontrol means for alternatively controlling the forward route gateelements and the reverse route gate elements to open or close toswitchably select forward direction signal transmission processing fromthe front stage side signal transmission blocks to the rear stage sidesignal transmission blocks and reverse direction signal transmissionprocessing from the rear stage side signal transmission blocks to thefront stage side signal transmission blocks.

The bidirectional signal transmission network having the constructioncan be applied, for example, to a drive circuit for a two-dimensionaladdress device. In particular, according to a still further aspect ofthe present invention, there is provided a two-dimensional addressdevice which includes a row scanning line group, a column scanning linegroup, and a group of active elements disposed corresponding toindividual crossing points between the two scanning line groups,comprising a drive circuit connected to at least one of the scanningline groups for successively supplying a drive signal to the scanningline group, the drive circuit including a plurality of signaltransmission blocks each having an input terminal and an outputterminal, the input and output terminals of the signal transmissionblocks being connected successively, the output terminals of the signaltransmission blocks being individually connected to correspondingscanning lines of the one scanning line group, a forward route gateelement interposed in a connection route between the output terminal ofthe front stage side one of each two adjacent front and rear ones of thesignal transmission blocks and the input terminal of the rear stage sidesignal transmission block, and a reverse route gate element interposedin another connection route between the output terminal of the rearstage side one of each two adjacent front and rear ones of the signaltransmission blocks and the input terminal of the front stage sidesignal transmission block, whereby the forward route gate elements andthe reverse route gate elements are alternatively controlled to open orclose to switchably select forward direction signal transmissionprocessing from the front stage side signal transmission blocks to therear stage side signal transmission blocks and reverse direction signaltransmission processing from the rear stage side signal transmissionblocks to the front stage side signal transmission blocks.

According to the present invention, the bidirectional signaltransmission network is realized with the simple structure that aforward route gate element is interposed in a connection route betweenthe output terminal of the front stage side one of each two adjacentfront and rear ones of signal transmission blocks and the input terminalof the rear stage side signal transmission block and a reverse routegate element is interposed in another connection route between theoutput terminal of the rear stage side one of each two adjacent frontand rear ones of the signal transmission blocks and the input terminalof the front stage side signal transmission block. By alternativelycontrolling the forward route gate elements and the reverse route gateelements to open or close, forward direction signal transmissionprocessing and reverse direction signal transmission processing can beswitchably selected. For example, by connecting flipflops as the signaltransmission blocks in multiple stages, a bidirectional signal transfershift register can be obtained readily. By incorporating thebidirectional signal transfer shift register into a drive circuit for anactive matrix liquid crystal display device, selective reversed displayof an image can be realized readily. Further, by incorporating thebidirectional signal transmission network into a drive circuit for atwo-dimensional address device, bidirectional two-dimensional addressingcan be achieved readily.

The above and other objects, features and advantages of the presentinvention will become apparent from the following description and theappended claims, taken in conjunction with the accompanying drawings inwhich like parts or elements are denoted by like reference characters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a basic construction of abidirectional signal transfer shift register according to the presentinvention;

FIGS. 2(A) and 2(B) are block diagrams illustrating different operationsof the bidirectional signal transfer shift register shown in FIG. 1;

FIG. 3 is a circuit diagram showing a detailed construction of thebidirectional signal transfer shift register shown in FIG. 1;

FIG. 4 is a block diagram showing a bidirectional signal transmissionnetwork to which the present invention is applied;

FIG. 5 is a schematic circuit diagram an active matrix liquid crystaldisplay device in which a bidirectional signal transfer shift registeraccording to the present invention is incorporated;

FIG. 6 is a schematic perspective view showing a general construction ofan active matrix liquid crystal display device;

FIG. 7 is a block diagram showing an exemplary one of conventional imagereversing systems; and

FIG. 8 is a block diagram showing another conventional image reversingsystem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, there is shown a basic construction of abidirectional signal transfer shift register according to the presentinvention. The present shift register has a multi-stage structure whichincludes a plurality of flipflops FF each including an input terminal INand an output terminal OT in pair and wherein the input and outputterminals of the flipflops FF are connected successively. It is to benoted that, in the arrangement shown in FIG. 1, the flipflops FF have amulti-stage connection of three stages of the first to third stages inorder to facilitate understanding. When an actual application isintended, there is no special limitation in such number of stages. Aforward route gate element R is interposed in a connection line betweenthe front stage side output terminal and the rear stage side inputterminal of each adjacent front and rear ones of the flipflops FF whilea reverse route gate element L is interposed in another connection linebetween the rear stage side output terminal and the front stage sideinput terminal. For example, if it is assumed that, in the multi-stageconnection shown, the front stage side flipflop is the first flipflop FFand the rear stage side is the second flipflop FF, then a forward routegate element R is interposed in the connection route between the outputterminal OT of the first flipflop FF and the input terminal IN of thesecond flipflop FF. Meanwhile, a reverse route gate element L isinterposed in the connection route between the output terminal OT of thesecond flipflop FF and the input terminal IN of the first flipflop FF.By alternatively controlling the forward route gate elements R and thereverse route gate elements L to open or close, forward direction signaltransfer from the front stage side to the rear stage side (signaltransfer from the left side to the right side in FIG. 1) and reversedirection signal transfer from the rear stage side to the front stageside (signal transfer from the right side to the left side in FIG. 1)can be switchably selected.

Operation of the bidirectional signal transfer shift register shown inFIG. 1 will be described in detail with reference to FIGS. 2(A) and2(B). FIG. 2(A) illustrates forward direction signal transfer. In theforward direction signal transfer, the forward route gate elements R areopen which the reverse route gate elements L are closed. Consequently, astart signal ST first passes the first forward route gate element R andis then supplied to the input terminal IN of the first flipflop FF asindicated by an arrow mark. The first flipflop FF processes the startsignal ST in synchronism with a clock signal and supplies the thusprocess signal to the output terminal OT thereof. The output signal issupplied to the input terminal IN of the second flipflop FF by way ofthe next forward route gate element R. Similarly, the second flipflop FFexecutes internal processing of the signal transferred thereto and thensupplies the thus processed signal to the output sterminal OT thereof.The output signal is transferred to the input terminal IN of the thirdflipflop FF by way of the next forward route gate element R. Finally,the output signal of the third flipflop FF is transmitted to the lastforward route gate element R.

FIG. 2(B) illustrates reverse direction signal transfer. In the reversedirection signal transfer, the reverse route gate elements L are openwhile the forward route gate elements R are closed. The start signal STcannot be supplied to the input terminal IN of the first flipflop FFsince the first forward route gate element R is closed. Instead, thestart signal ST passes the last reverse route gate element L by way of abypass route so that it is supplied to the input terminal IN of thethird flipflop FF. The transfer signal is processed by internalprocessing by the third flipflop FF and then supplied from the outputterminal OT of the third flipflop FF to the input terminal IN of thesecond flipflop FF by way of the next reverse route gate element L.After the transfer signal is processed by internal processing by thesecond flipflop FF, it is supplied from the output terminal OT of thesecond flipflop FF to the input terminal IN of the first flipflop FF byway of the next reverse route gate element L. The transfer signalprocessed by internal processing by the first flipflop FF is thentransmitted from the output terminal OT of the first flipflop FF to thetop reverse route gate element L.

FIG. 3 shows an exemplary detailed circuit construction of thebidirectional signal transfer shift register shown in FIG. 1. In orderto simplify the illustration, only the first flipflop FF, the secondflipflop FF, and forward route gate elements R and reverse route gateelements L associated with them are shown. In the arrangement shown, allcircuit elements are constituted from thin film transistors (TFTs).However, the circuit elements may alternatively be bipolar transistorsor MOS transistors. The first flipflop FF and the second flipflop FF areboth constituted from D-type flipflops and make signal transmissionblocks of the clock controlled type. The D-type flipflops are eachconstituted from first and second clock invertors and a third invertorand operate in response to clock signals CK1 and CK2 of opposite phasesto each other to delay a signal inputted thereto from the input terminalIN by a half period of the clock signals and output the delayed signalto the output terminal OT. Each of the forward route gate elements R isconstituted from a transmission gate element of the CMOS type, and alsoeach of the reverse route gate elements L is similarly constituted froma transmission gate element. It is to be noted that analog switches onlyof the NMOS or PMOS type may alternatively be utilized as the gateelements. The forward route gate elements R and reverse route gateelements L are controlled by control signals CTR and CTL of oppositephases to each other supplied thereto from control means. When thecontrol signal CTR is at a high level and the other control signal CTLis at a low level, the forward route gate elements R are opened whilethe reverse route gate elements L are closed. Accordingly, in thisinstance, the start signal ST first passes the first forward route gateelement R and is then supplied to the input terminal IN of the firstflipflop FF. After the start signal ST is processed by delayingprocessing by a half period of the clock signals by the first flipflopFF, it is transferred from the output terminal OT of the first flipflopFF to the input terminal IN of the second flipflop FF by way of the nextforward route gate element R. The start signal ST is transferredsuccessively in the forward direction in this manner. On the other hand,when the control signal CTR is changed over to a low level and thecontrol signal CTL is changed over to a high level, the forward routegate elements R are closed while the reverse route gate elements L areopened. In this instance, a signal having been transferred in thereverse direction is supplied to the input terminal IN of the secondflipflop FF and processed by predetermined delaying processing by thesecond flipflop FF, and then it is transferred from the output terminalOT of the second flipflop FF to the input terminal IN of the firstflipflop FF by way of the associated reverse route gate element L. Afterthe transfer signal is processed by predetermined delaying processing bythe first flipflop FF, it is outputted from the output terminal OT ofthe first flipflop FF and received by the next reverse route gateelement L.

While, in the embodiments described above, a shift register whereinflipflops are connected in multiple stages is described as a signaltransmission block, the present invention can be applied to any ordinarybidirectional signal transmission network. A generalized bidirectionalsignal transmission network has a multi-stage structure which includes aplurality of signal transmission blocks each having an input terminal ofa comparatively high impedance and an output terminal of a comparativelylow impedance and wherein the input and output terminals aresuccessively connected. A forward route gate element is interposed in aconnection route between the front stage side output terminal and therear stage side input terminal of each adjacent front and rear ones ofthe signal transmission blocks. Meanwhile, a reverse route gate elementis interposed in another connection route between the rear stage sideoutput terminal and the front stage side input terminal. The forwardroute gate elements and the reverse route gate elements can bealternatively controlled to open or close to switchably select forwarddirection signal transfer processing and reverse direction signaltransfer processing. FIG. 4 shows, as another example of suchbidirectional signal transmission network, a bidirectional signal delaynetwork wherein invertors are connected in multiple stages. Referring toFIG. 4, a forward direction input signal INR is processed by delayingprocessing at multiple stages by way of forward route gate elements Rand invertors INV so that a forward direction output signal OTR isobtained. On the other hand, a reverse direction input signal INL issimilarly processed by multi-stage delaying processing by way of reverseroute gate elements L and the invertors INV so that a reverse directionoutput signal OTL is obtained.

Finally, an active matrix liquid crystal display device to which thepresent invention is applied will be described in detail with referenceto FIG. 5. The active matrix liquid crystal display device has a flatpanel structure which includes a pair of substrates disposed in anopposing relationship to each other with a predetermined gap lefttherebetween, and a liquid crystal layer held in the gap. Formed on oneof the substrates are n gate lines X₁, X₂, . . . , X_(n) disposed alongthe direction of a row of a matrix, m data lines Y₁, Y₂, . . . , Y_(m)disposed along the direction of a column of the matrix, active elementsT₁₁, T₁₂, T₂₁, T₂₂, . . . from thin film transistors and positioned atcrossing points of the gate lines and the data lines, picture elementelectrodes driven by the individual active elements, a vertical drivecircuit 10 for line-sequentially supplying a gate signal to the gatelines X₁, X₂, . . . , X_(n), and a horizontal drive circuit 20 forline-sequentially supplying a data signal SIG to the data lines Y₁, Y₂,. . . , Y_(m) by way of switching elements S₁, S₂, . . . , S_(m). Aplurality of opposing electrodes COM are formed on the other substrateand construct liquid crystal picture elements L₁₁, L₁₂, L₂₁, L₂₂, . . .together with the individual picture element electrodes to form adesired image in response to potential differences from the pictureelement electrodes. In the construction described above, at least one ofthe vertical drive circuit 10 and the horizontal drive circuit 20includes a bidirectional shift register which can switchably control theline sequential supplying order of a signal between the two forward andreverse directions so that reversal display of an image may be performedselectively. Where the vertical drive circuit 10 includes abidirectional shift register, vertically reversed display of an image isallowed selectively. In particular, when a gate signal is successivelysupplied beginning with the gate line X1 and ending with the gate lineXn by the vertical drive circuit 10, a normal or non-reversed display isobtained, but on the contrary when a gate signal is successivelysupplied beginning with the gate line Xn and ending with the gate lineX1, a vertically reversed display is obtained. Similarly, where thehorizontal drive circuit 20 includes a bidirectional shift register,leftwardly and rightwardly reversed display of an image is allowedselectively. In particular, when the switching elements S1 to Sm arescanned in the direction from switching element S1 toward the switchingelement Sm by the horizontal drive circuit 20, a normal or non-reverseddisplay can be obtained. On the contrary, when the switching elements S1to Sm are scanned from the switching element Sm toward the switchingelement S1, a leftwardly and rightwardly reversed display can beobtained.

Having now fully described the invention, it will be apparent to one ofordinary skill in the art that many changes and modifications can bemade thereto without departing from the spirit and scope of theinvention as set forth herein.

What is claimed is:
 1. An arrangement for preparing image data fordisplay, comprising:means for selectively implementing a reflectionreversal of the image data, including:a plurality of signal transmissionblocks each having an input terminal of a comparatively high impedanceand an output terminal of a comparatively low impedance, the input andoutput terminals of said signal transmission blocks being connectedsuccessively; a forward route switch element interposed in a connectionroute between the output terminal of the front stage side one of eachtwo adjacent front and rear ones of said signal transmission blocks andthe input terminal of the rear stage side signal transmission block,said forward route switch selectively transmittting image data, saidforward route switch remaining in one of an open position and a closedposition during data transmission; a reverse route switch elementinterposed in another connection route between the output terminal ofthe rear stage side one of each two adjacent front and rear ones of saidsignal transmission blocks and the input terminal of the front stageside signal transmission block, said reverse route switch selectivelytransmittting image data, said reverse route switch remaining in one ofan open position and a closed position during data transmission; saidconnection route and said another connection route being parallel to oneanother, and said forward route switch element and said reverse routeswitch element alternating in said connection routes, and control meansfor alternatively controlling the forward route switch elements and thereverse route switch elements to open or close to switchably selectforward direction signal transmission processing from the front stageside signal transmission blocks to the rear stage side signaltransmission blocks and reverse direction signal transmission processingfrom the rear stage side signal transmission blocks to the front stageside signal transmission blocks, only a single one of said forward routeswitch elements being connected between each pair of adjacent ones ofsaid signal transmission blocks during forward direction signaltransmission processing and only a single one of said reverse routeswitch elements being connected between each pair of adjacent ones ofsaid signal transmission blocks during reverse direction signaltransmission processing.
 2. An image reversal apparatus,comprising:means for at least one of reversing and inverting image datafor display, including:a bidirectional signal transfer shift registerhaving:a plurality of flipflops each having an input terminal and anoutput terminal in pair, the input and output terminals of saidflipflops being connected successively in such a manner as to constructa multistage structure; a forward route switch element interposed in aconnection route between the output terminal of the front stage side oneof each two adjacent front and rear ones of said flipflops and the inputterminal of the rear stage side flipflops, said forward route switchelement being switchable from a transmitting to a non-transmitting stateby control signals that remain in a state determinative of switchingdirection without change at each clock signal; a reverse route switchelement interposed in another connection route between the outputterminal of the rear stage side one of each two adjacent front and rearones of said flip flops and the input terminal of the front stage sideflipflop, said reverse route switch element being switchable from atransmitting to a non-transmitting state by control signals that remainin a state determinative of switching direction without change at eachclock signal; and said connection route and said another connectionroute being parallel to one another, said forward route switch elementand said reverse switch element alternating in said connection routes,only a single one of said forward route switch elements being connectedbetween each pair of adjacent ones of said flip-flops during forwarddirection signal transmission processing and only a single one of saidreverse route switch elements being connected between each pair ofadjacent ones of said flip-flops during reverse direction signaltransmission processing.
 3. An active matrix liquid crystal displaydevice for selective projection in one of a plurality of orientations,comprising:means for selectively reversing orientation of an imagesignal depending on projection orientation, including:a first substrateon which a plurality of gate lines disposed along the direction of a rowof a matrix, a plurality of data lines disposed along the direction of acolumn of the matrix, a plurality of active elements positioned atcrossing points between said gate lines and said data lines, a pluralityof picture element electrodes individually driven by said activeelements, a vertical drive circuit for supplying a gate signalline-sequentially to said gate lines, and a horizontal drive circuit forsupplying a data signal line-sequentially to said data lines are formed;a second substrate disposed in an opposing relationship to said firstsubstrate and having a plurality of opposing electrodes formed thereon;a liquid crystal layer held in a gap between said first and secondsubstrates; and a bidirectional shift register capable of switchablycontrolling the line sequential supplying order of the gate signal orthe data signal between two forward and reverse directions, saidbidirectional signal transfer shift register having:a plurality offlipflops each having an input terminal and an output terminal in pair,the input and output terminals of said flipflops being connectedsuccessively in such a manner as to construct a multistage structure; aforward route switch element interposed in a connection route betweenthe output terminal of the front stage side one of each two adjacentfront and rear ones of said flipflops and the input terminal of the rearstage side flipflops, said forward route switch element being switchablefrom a transmitting to a non-transmitting state by control signals thatremain in a state determinative of switching direction without change ateach clock signal; a reverse route switch element interposed in anotherconnection route between the output terminal of the rear stage side oneof each two adjacent front and rear ones of said flip flops and theinput terminal of the front stage side flipflop, said reverse routeswitch element being switchable from a transmitting to anon-transmitting state by control signals that remain in a statedeterminative of switching direction without change at each clocksignal, only a single one of said forward route switch elements beingconnected between each pair of adjacent ones of said flip-flops duringforward direction signal transmission processing and only a single oneof said reverse route switch elements being connected between each pairof adjacent ones of said flip-flops during reverse direction signaltransmission processing.
 4. An active matrix liquid crystal displaydevice according to claim 3, wherein said bidirectional shift registeris included in said vertical drive circuit so as to selectively allowvertically reversed display of an image.
 5. An active matrix liquidcrystal display device according to claim 3, wherein said bidirectionalshift register is included in said horizontal drive circuit so as toselectively allow leftwardly and rightwardly reversed display of animage.
 6. An active matrix liquid crystal display device according toclaim 3, wherein said bidirectional shift register includes a pluralityof flipflops each having an input terminal and an output terminal inpair, the input and output terminals of said flipflops being connectedsuccessively in such a manner as to construct a multi-stage structure.7. An active matrix liquid crystal display device according to claim 6,wherein said bidirectional shift register further includes a forwardroute gate element interposed in a connection route between the outputterminal of the front stage side one of each two adjacent front and rearones of said flipflops and the input terminal of the rear stage sideflipflop, and a reverse route gate element interposed in anotherconnection route between the output terminal of the rear stage side oneof each two adjacent front and rear ones of said flipflops and the inputterminal of the front stage side flipflop, the forward route gateelements and the reverse route gate elements being alternativelycontrolled to open or close to switchably select forward directionsignal transfer from the front stage side flipflops to the rear stageside flipflops and reverse direction signal transfer from the rear stageside flipflops to the front stage side flipflops.
 8. In a display havinga selectable image orientation, a two-dimensional address device whichincludes a row scanning line group, a column scanning line group, and agroup of active elements disposed corresponding to individual crossingpoints between the two scanning line groups, comprising;a drive circuitconnected to at least one of the scanning line groups for successivelysupplying a drive signal to the scanning line group, said drive circuitincluding a plurality of signal transmission blocks each having an inputterminal and an output terminal, the input and output terminals of saidsignal transmission blocks being connected successively, the outputterminals of said signal transmission blocks being individuallyconnected to corresponding scanning lines of the one scanning linegroup; a forward route switch element interposed in a connection routebetween the output terminal of the front stage side one of each twoadjacent front and rear ones of said signal transmission blocks and theinput terminal of the rear stage side signal transmission block; and areverse route switch element interposed in another connection routebetween the output terminal of the rear stage side one of each twoadjacent front and rear ones of said signal transmission blocks and theinput terminal of the front stage side signal transmission block; theforward route switch elements and the reverse route switch elements arealternatively controlled to open or close under control of a controlsignal which does not change at each clock signal to switchably selectforward direction signal transmission processing from the front stageside signal transmission blocks to the rear stage side signaltransmission blocks and reverse direction signal transmission processingfrom the rear stage side signal transmission blocks to the front stageside signal transmission blocks, only a single one of said forward routeswitch elements being connected between each pair of adjacent ones ofsaid signal transmission blocks during forward direction signaltransmission processing and only a single one of said reverse routeswitch elements being connected between each pair of adjacent ones ofsaid signal transmission blocks during reverse direction signaltransmission processing.